Two-Part Polyurethane Adhesive for Elastomer Bonding

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Solution Overview

Problem

Existing polyurethane adhesives face challenges in bonding non-polar elastomeric surfaces, requiring primers or surface treatments, and often rely on solvents, which are hazardous and limit their effectiveness, especially in field repairs of rubber-based articles like conveyor belts.

Innovation Solution

A two-part polyurethane adhesive formulation that includes a polyol, adhesion promoter, chain extender, catalyst, and water scavenger in Part A, and a polyurethane prepolymer and plasticizer in Part B, which can be cured without priming or solvents, providing a strong bond to elastomeric substrates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional polyurethane adhesives are used for bonding elastomeric surfaces, then adhesion can be improved by applying primers or surface treatments, but the process complexity and cost increase significantly

Engineering Contradiction:
Improveadhesion strengthVSAvoidprocess complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the primer component from the adhesive system. The polyurethane adhesive formulation is designed to bond directly to elastomeric surfaces without requiring a separate primer application, thereby simplifying the bonding process while maintaining adhesion strength

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The adhesive system is segmented into two components (Part A and Part B) that are mixed immediately before application. This segmentation allows the adhesive to remain stable during storage while providing optimal bonding performance when activated, eliminating the need for primers

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If solvents are included in polyurethane adhesives to improve application properties, then ease of application increases, but health hazards and environmental concerns worsen

Engineering Contradiction:
Improveease of applicationVSAvoidhealth hazards
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical and chemical parameters of the adhesive formulation by eliminating organic solvents. The adhesive achieves proper viscosity and application properties through the selection of specific polyol components and their ratios, rather than relying on solvent content

Inventive Principle:
Principle #35Parameter changes

3Strength

If surface treatments are applied to elastomers to improve adhesion, then bonding strength increases, but the duration of surface activity is limited before reversion to pre-treatment levels

Engineering Contradiction:
Improvebonding strengthVSAvoidduration of surface activity
Core Design Contradiction:
StrengthVSDuration of action of stationary object

Solution Approach 1:

The adhesive formulation incorporates adhesion promoters that are activated upon mixing Part A and Part B. These promoters prepare the adhesive interface in advance to ensure optimal bonding to elastomeric surfaces, with the chemical activity sustained throughout the curing process rather than reverting

Inventive Principle:
Principle #10Preliminary action

4Strength

If primers are required for rubber bonding to achieve adequate adhesion, then bonding strength improves, but field repair difficulty and time increase

Engineering Contradiction:
Improveadhesion strengthVSAvoidfield repair ease
Core Design Contradiction:
StrengthVSEase of repair

Solution Approach 1:

The adhesive is provided as a two-component system that can be mixed in portable containers at the site of repair. The segmentation into Part A and Part B allows for simple field mixing without requiring primer application equipment or specialized surface treatment facilities

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The primer step is completely removed from the field repair process. The polyurethane adhesive formulation bonds directly to rubber surfaces without requiring any separate primer application, making field repairs straightforward and reliable

Inventive Principle:
Principle #2Taking out (Extraction)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The adhesive achieves high strength bonds without primers or solvents, facilitating field repairs and extending the longevity of elastomeric articles, with superior mechanical properties and thermal stability, suitable for a wide range of elastomers and environments.

Implementation Method 1

The adhesive having a Part A including at least a polyol, an adhesion promoter, a chain extender, a catalyst and a water scavenger; and a Part B includes at least polyurethane prepolymer and a plasticizer. The two part adhesive formulation is cured to form the adhesive.

Methodology Applied
Scientific EffectPolymerization: Photopolymerisation

Implementation Method 2

a polyol, an adhesion promoter, a chain extender

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentUS10202527B2Primer-less two component polyurethane adhesive
Publication Date: 2019.02.12 ILLINOIS TOOL WORKS INC

AI summary

A process of applying an adhesive to an elastomer includes the application to the elastomer of a two part adhesive formulation. The adhesive having a Part A including at least a polyol, an adhesion promoter, a chain extender, a catalyst, a water scavenger; and a Part B comprising: polyurethane prepolymer, adhesion promoter and a plasticizer. The two part adhesive formulation is cured to form the adhesive. In contrast to the prior art, no priming or surface activation is required to obtain a high strength bond to the elastomer. The resulting article of an elastomer with the resultant adhesive is sufficiently strong to result in surface peel off of the elastomer. A kit is provided for the repair of an elastomer without resort to priming the elastomer.